Search

In this paper we present a global fit of beyond the Standard Model (BSM) dimension-six operators relevant to the top quark sector to all currently available top production cross-section measurements, namely parton-level top-pair and single top production at the LHC and the Tevatron. Higher order QCD corrections are modeled using differential and global K-factors, and we use novel fast-fitting techniques developed in the context of Monte Carlo event generator tuning to perform the fit. This allows us to provide new, fully correlated and model-independent bounds on new physics effects in the top sector from the most current direct hadron-collider measurements in light of the involved theoretical and experimental systematics. As a by-product, our analysis constitutes a proof-of-principle that fast fitting of theory to data is possible in the top quark sector, and paves the way for a more detailed analysis including top quark decays, detector corrections and precision observables. [ABSTRACT FROM AUTHOR]

Top quark loops in Higgs production via gluon fusion at large invariant final state masses can induce important interference effects in searches for additional Higgs bosons as predicted in, e.g., Higgs portal scenarios and the minimal supersymmetric Standard Model when the heavy scalar is broad or the final state resolution is poor. Currently, the limit setting as performed by both ATLAS and CMS is based on injecting a heavy Higgs-like signal neglecting interference effects. In this paper, we perform a study of such "on-shell" interference effects in pp → ZZ and find that they lead to a ≲ O(30%) width scheme-dependent modification of the signal strength. Including the continuum contributions to obtain, e.g., the full pp → ZZ → 4ℓ final state, this modification is reduced to the 10% level in the considered intermediate mass range. [ABSTRACT FROM AUTHOR]

Indirect constraints on the total Higgs width Γh from correlating Higgs signal strengths with cross-section measurements in the off-shell region for p(g)p(g) → 4l production have received considerable attention recently, and the CMS Collaboration have published a first measurement. We revisit this analysis from a new physics and unitarity constraints perspective and conclude that limits on Γh obtained in this fashion are not reliable unless we make model-specific assumptions, which cannot be justified at the current stage of the LHC program. Relaxing the Γh interpretation, we discuss the merits of high invariant mass cross-section measurements in the context of Higgs CP analyses, higher-dimensional operator testing, and resolved new physics in the light of electroweak precision constraints beyond effective theory limitations. Furthermore, we show that a rather model-independent LHC constraint can be obtained from adapting the gg → 4l analysis to the weak boson fusion channels at lower statistical yield. [ABSTRACT FROM AUTHOR]

In the Standard Model, the Higgs coupling to gluons is almost entirely induced by top quark loops. We derive the logarithmic structure of Higgs production in association with two jets. Just like in the one-jet case, the transverse momentum distributions exhibit logarithms of the top quark mass and can be used to test the nature of the loop-induced Higgs coupling to gluons. Using Higgs decays to W bosons and to tau leptons, we show how the corresponding analyses hugely benefit from the second jet in the relevant signal rate as well as in the background rejection. [ABSTRACT FROM AUTHOR]

The top quark, being the heaviest particle of the Standard Model (SM), is a prime candidate of where physics beyond the SM (BSM) might currently hide before our eyes. There are many natural extensions of the SM that rely on top compositeness, and the top quark could follow the paradigm of revealing a substructure when it is probed at high enough momentum transfers. Observing high pr top final states naturally drives us toward boosted hadronic analyses that can be tackled efficiendy with jet substructure techniques. In this paper we analyze the prospects of constraining exemplary nonstandard QCD top interactions in this kinematical regime. We correctly include QCD modifications to additional gluon emission off the boosted top quark and keep track of the modified top tagging eificiencies. We conclude that nonstandard top QCD interactions can be formidably constrained at the LHC 14 TeV. Experimental systematic uncertainties are a major obstacle of the described measurement. Unless significantly improved for the 14 TeV run, they will saturate the direct sensitivity to nonresonant BSM top physics at luminosities of around 100/fb. [ABSTRACT FROM AUTHOR]

After the discovery of the 125 GeV scalar boson with gauge properties similar to the Standard Model (SM) Higgs, the search for beyond the SM interactions will focus on studying the discovered particles' coupling properties more precisely and shedding light on the relation of fermion masses with the electroweak vacuum. The large mass of the top quark and the SM-predicted order one top Yukawa coupling is a natural candidate for beyond the SM physics, though experimentally challenging to constrain. In this paper, we argue that investigating angular correlations in pp → τHj production provides an excellent handle to constrain the top Yukawa coupling yt, via direct measurements, even when we focus on rare exclusive final states. We perform a hadron-level analysis and show that we may expect to constrain yt, ≳ 0.5ytSM at 95%-99% confidence level at the high luminosity LHC using semileptonic top decays and H → γγ alone, by employing a two-channel measurement approach. [ABSTRACT FROM AUTHOR]

Analyses of boosted Higgs bosons from associated production comprise some of the main search channels for the Higgs boson at the LHC. The gluon-initiated gg → hZ subprocess has largely been ignored in phenomenological analyses of boosted associated production although this contribution is sizable as the pT spectrum for this process is maximized in the boosted regime due to the top quark loop threshold. In this paper, we discuss this contribution to boosted pp → hZ analyses in detail. We find there are previously overlooked modifications of standard model Higgs rates at the LHC which depend on the pT cuts applied and can be significant. There are also important consequences for physics beyond the standard model as the gg → hZ process introduces significant dependence on the magnitude and sign of the Higgs-top quark coupling c„ which is overlooked if it is assumed that associated production depends only on the Higgs-Z boson coupling as c²v. This new dependence on ct impacts interpretations of Higgs rates in the contexts of supersymmetry, two Higgs doublet models, and general scenarios with modified couplings. We suggest that these effects be included in current and future LHC boosted Higgs analyses. [ABSTRACT FROM AUTHOR]

Extensions of the standard model Higgs sector involving weak isotriplet scalars are not only benchmark candidates to reconcile observed anomalies of the recently discovered Higgs-like particle, but also exhibit a vast parameter space, for which the lightest Higgs' phenomenology turns out to be very similar to the standard model one. A generic prediction of this model class is the appearance of exotic doubly charged scalar particles. In this paper we adapt existing dilepton+missing energy+jets measurements in the context of supersymmetry searches to the dominant decay mode H±±→W±W± and find that the LHC already starts probing the model's parameter space. A simple modification toward signatures typical of weak boson fusion searches allows us to formulate even tighter constraints with the 7 TeV LHC data set. A corresponding analysis of this channel performed at 14 TeV center-of-mass energy will constrain the model over the entire parameter space and facilitate potential H±±→W±W± discoveries. [ABSTRACT FROM AUTHOR]

After the discovery of a Higgs-like particle at the LHC, the determination of its spin quantum numbers across different channels will be the next step in arriving at a more precise understanding of the new state and its role in electroweak symmetry breaking. Event shape observables have been shown to provide extremely sensitive observables for the discrimination of the scalar Higgs boson's CT quantum numbers as a consequence of the different radiation patterns of Higgs production via gluon fusion vs weak boson fusion in the pp → X + 2j selection. We show that a similar strategy serves to constrain the spin quantum numbers of the discovered particle as a function of the involved couplings. We also discuss the prospects of applying a similar strategy to future discoveries of Higgs-like particles. [ABSTRACT FROM AUTHOR]

ATLAS and CMS have discovered a standard model (SM) Higgs-like particle. One of the main discovery channels is the Higgs decay to two photons, which, at the moment, seems to be considerably enhanced over the standard model expectation. Models with additional charged matter coupling to the Higgs sector can enhance or decrease the h → ɣɣ branching ratio. We take this as motivation to confront the so-called Georgi-Machacek model of Higgs triplets with the results of recent searches for a SM Higgs boson performed at the LHC. We also investigate the model in regions of the allowed parameter space relevant for a SM-like phenomenology. The Georgi-Machacek model avoids tree-level issues of the T parameter, while offering a vastly modified Higgs phenomenology compared to the standard model. This comes at the price of introducing another fine-tuning problem related to electroweak precision measurements. We investigate the collider phenomenology of the Georgi-Machacek model in the light of existing collider constraints beyond any effective field theory approximation and contextualize our findings with electroweak precision constraints. [ABSTRACT FROM AUTHOR]

Multi-Higgs production provides a phenomenologically clear window to the electroweak symmetry-breaking sector. We perform a comprehensive and comparative analysis of new electroweak physics effects in di-Higgs and di-Higgs + jet production. In particular, we discuss resonant di-Higgs phenome-nology, which arises in the Higgs portal model and in the minimal supersymmetric Standard Model at small tan β, and nonresonant new-physics contributions to di-Higgs production in models where the newly discovered Higgs candidate is interpreted as a pseudo-Nambu-Goldstone boson. We show that, for all these scenarios, a measurement of the di-Higgs and di-Higgs + jet final states provides an accessible and elaborate handle to understand electroweak symmetry breaking in great detail. [ABSTRACT FROM AUTHOR]

After the recent discovery of a Standard Model Higgs bosonlike particle at the LHC, the question of its couplings to known and unknown matter is eminent. In this paper, we present a method that allows for an enhancement in signal over background (irreducible) of the order of 100% in pp →(h→ γγ )jj for a center of mass energy of 8 and 14 TeV. This is achieved by applying the matrix element method. We discuss the implications of detector resolution effects and various approximations of the involved event simulation and reconstruction. The matrix element method provides a reliable, stable, and efficient handle to separate signal from background and the gluon and weak boson fusion components involved in this process. Employing this method, a more precise Higgs boson coupling extraction can be obtained, and our results are of immediate relevance for current searches. [ABSTRACT FROM AUTHOR]

Recent measurements by the ATLAS and CMS experiments have excluded the standard model Higgs boson in the high mass region, even if it is produced with a significantly smaller cross section than expected. The bounds are dominated by the nonobservation of a signal in the clean gold-plated mode h → ZZ → 4ℓ and, hence, are directly related to the special role of the Higgs in electroweak symmetry breaking. A smaller cross section in comparison to the standard model is expected if the Higgs is realized as an unparticle in the unHiggs scenario. With the LHC probing σ/σSM ﹤ 1, we can therefore reinterpret the h → ZZ → 4ℓ exclusion limits as bounds on the unHiggs' scaling dimension. Throughout the high Higgs mass range, where we expect a large signal in the presence of the standard model Higgs for the 2011 ATLAS and CMS data sets, the observed limits translate into mild bounds on the unHiggs scaling dimension in the high mass region. [ABSTRACT FROM AUTHOR]

We investigate whether or not perturbative unitarity is preserved in the unHiggs model for the scattering process of heavy quarks and longitudinal gauge bosons q¯q →V+LV-L. With the Yukawa coupling given in the original formulation of the unHiggs model, the model preserves unitarity for unHiggs scaling dimensions d ≤ 1.5. We examine the LHC phenomenology which is implied by the unHiggs model in this parameter range in detail and discuss to what extent the LHC can test d if an excess is measured in the phenomenologically clean ZZ channel in the future or if the LHC measurement remains consistent with the background. We then make use of the AdS/CFT correspondence to derive a new Yukawa coupling which is conformally invariant at high energies and show that with this Yukawa coupling, the theory is unitary for 1 ≤ d <2. [ABSTRACT FROM AUTHOR]

Nonstandard decays of the Higgs boson produced at the Large Hadron Collider can lead to signatures which can easily be missed due to nonadapted trigger or search strategies. Keeping electroweak symmetry breaking standard model-like, we classify the phenomenology of an evasive Higgs boson into three categories and discuss how they can be described in an effective field theory. We comment on how one can improve the search strategies to also detect such an evasive Higgs [ABSTRACT FROM AUTHOR]

Understanding and identifying ditau jets--jets consisting of pairs of tau particles--can be of crucial importance and may even turn out to be a necessity if the Higgs boson decays dominantly to new light scalars which, on the other hand, decay to tau pairs. As often seen in various models beyond the standard model such as in the next-to-minimal supersymmetric standard model, Higgs portals, etc., the lightness of these new states ensures their large transverse momenta and, as a consequence, the collinearity of their decay products. We show that the nonstandard signatures of these objects, which can easily be missed by standard analysis techniques, can be superbly exploited in an analysis based on subjet observables. When combined with additional selection strategies, this analysis can even facilitate an early discovery of the Higgs boson. To be specific, a light Higgs can be found with S/ √B ≳ 5 from Ꮭ ≃ 12 fb-1 of data. We combine all these observables into a single discriminating likelihood that can be employed toward the construction of a realistic and standalone ditau tagger. [ABSTRACT FROM AUTHOR]

Jets plus missing transverse energy is one of the main search channels for new physics at the LHC. A major limitation lies in our understanding of QCD backgrounds. Using jet merging, we can describe the number of jets in typical background channels in terms of a staircase scaling, including theory uncertainties. The scaling parameter depends on the particles in the final state and on cuts applied. Measuring the staircase scaling will allow us to also predict the effective mass for standard model backgrounds. Based on both observables, we propose an analysis strategy avoiding model-specific cuts, which returns information about the color charge and the mass scale of the underlying new physics. [ABSTRACT FROM AUTHOR]

Beyond the Standard Model scenarios with extensions of the Higgs sector typically predict new resonances that can undergo a series of cascade decays to detectable Standard Model particles. On one hand, sensitivity to such signatures will contribute to the full reconstruction of the extended Higgs potential if a new physics discovery will be made. On the other hand, such cascade decays could be dominant decay channels, thus being potentially the best motivated signatures to achieve a new physics discovery in the first place. In this work, we show how the long short-term memory that is encoded in the cascade decays' phenomenology can be exploited in discriminating the signal from the background, where no such information is present. In parallel, we demonstrate for theoretically motivated scenarios that such an approach provides improved sensitivity compared to more standard analyses, where only information about the signal's final state kinematics is included. [ABSTRACT FROM AUTHOR]

Partial top quark compositeness is a crucial aspect of theories with strong electroweak symmetry breaking. Together with the heavy top partners that lift the top quark mass to its observed value, these theories predict correlated modifications of the top quark's electroweak couplings. Associated measurements therefore provide direct constraints on the ultraviolet structure of the underlying hypercolor dynamics. In this paper, we employ a minimal version of top compositeness to discuss how measurements related to the top's electroweak gauge interactions can inform the potential composite nature of the TeV scale. In doing so, we identify the dominant factors that limit the beyond the Standard Model sensitivity. Extrapolating to a future 100 TeV hadron collider, we demonstrate that top quark measurements performed at highest precision can provide additional information to resonance search by performing a representative resonant top partner search that specifically targets the correlated resonant electroweak top partner signatures. [ABSTRACT FROM AUTHOR]

The search for di-Higgs final states is typically limited at the LHC to the dominant gluon fusion channels, with weak boson fusion only assuming a spectator role. In this work, we demonstrate that when it comes to searches for resonant structures that arise from isosinglet mixing in the Higgs sector, the weak boson fusion sideline can indeed contribute to winning the discovery game. Extending existing experimental resonance searches by including both contributions is therefore crucial. [ABSTRACT FROM AUTHOR]

Effective field theory (EFT) approaches are widely used at the Large Hadron Collider (LHC), such that it is important to study their validity and ease of matching to specific new physics models. In this paper, we consider an extension of the Standard Model (SM) in which a top quark couples to a new heavy scalar. We find the dimension six operators generated by this theory at low energy and match the EFT to the full theory up to the next-to-leading order (NLO) precision in the simplified model coupling. We then examine the range of validity of the EFT description in top pair production, finding excellent validity even if the scalar mass is only slightly above LHC energies, provided NLO corrections are included. In the absence of the latter, the LO EFT overestimates kinematic distributions, such that overoptimistic constraints on beyond the Standard Model (BSM) contributions are obtained. We next examine the constraints on the EFT and full models that are expected to be obtained from both top pair and four top production at the LHC, finding for low scalar masses that both processes show similar exclusion power. However, for larger masses, estimated LHC uncertainties push constraints into the nonperturbative regime, where the full model is difficult to analyze, and thus is not perturbatively matchable to the EFT. This highlights the necessity to improve uncertainties of SM hypotheses in top final states. [ABSTRACT FROM AUTHOR]

A coupling of a scalar, charged under an unbroken global U(1) symmetry, to the Standard Model via the Higgs portal is one of the simplest gateways to a dark sector. Yet, for masses mS≥mH/2 there are few probes of such an interaction. In this note, we evaluate the sensitivity to the Higgs portal coupling of di-Higgs boson production at the LHC as well as at a future high-energy hadron collider, FCC-hh, taking into account the full momentum dependence of the process. This significantly impacts the sensitivity compared to estimates of changes in the Higgs coupling based on the effective potential. We also compare our findings to precision single Higgs-boson probes such as the cross section for vector-boson-associated Higgs production at a future lepton collider, e.g., FCC-ee, as well as searches for missing energy-based signatures. [ABSTRACT FROM AUTHOR]

Constraining CP-violating interactions in effective field theory of dimension six faces two challenges. First, degeneracies in the multidimensional space of Wilson coefficients have to be lifted. Second, quadratic contributions of CP-odd dimension-six operators are difficult to disentangle from squared contributions of CP-even dimension-six operators and from linear contributions of dimension-eight operators. Both of these problems are present when new sources of CP violation are present in the interactions between the Higgs boson and heavy strongly interacting fermions. We show that degeneracies in the Wilson coefficients can be removed by combining measurements of Higgs-plus-two-jet production via gluon fusion with measurements of top-pair associated Higgs production. In addition, we demonstrate that the sensitivity of the analysis can be improved by exploiting the top-quark threshold in the gluon fusion process. Finally, we substantiate a perturbative argument about the validity of effective field theory by comparing the quadratic and linear contributions from CP-odd dimension-six operators and use this to show explicitly that high statistics measurements at future colliders enable the extraction of perturbatively robust constraints on the associated Wilson coefficients. [ABSTRACT FROM AUTHOR]

Many studies of possible new physics employ effective field theory (EFT), whereby corrections to the Standard Model take the form of higher-dimensional operators, suppressed by a large energy scale. Fits of such a theory to data typically use parton-level observables, which limits the data sets one can use. In order to theoretically model search channels involving many additional jets, it is important to include tree-level matrix elements matched to a parton shower algorithm, and a suitable matching procedure to remove the double counting of additional radiation. There are then two potential problems: (i) EFT corrections are absent in the shower, leading to an extra source of discontinuities in the matching procedure; (ii) the uncertainty in the matching procedure may be such that no additional constraints are obtained from observables sensitive to radiation. In this paper, we review why the first of these is not a problem in practice and perform a detailed study of the second. In particular, we quantify the additional constraints on EFT expected from top pair plus multijet events, relative to inclusive top pair production alone. [ABSTRACT FROM AUTHOR]

We study the process pp→Z(ℓ+ℓ-)h(b&b) in the standard model effective field theory (SMEFT) at high energies using subjet techniques to reconstruct the Higgs boson. We show that at high energies this process probes four directions in the dimension-6 EFT space, namely the operators that contribute to the four contact interactions, hZμfγμf, where f=uL,uR,dL and dR. These four directions are, however, already constrained by the Z-pole and diboson measurements at LEP. We show that by utilizing the energy growth of this process in the SMEFT and the accuracy that can be achieved by using subjet techniques at the High Luminosity LHC, one can obtain bounds on these operators that are an order of magnitude better than existing LEP bounds. [ABSTRACT FROM AUTHOR]

Nonminimal composite Higgs scenarios can contain exotic Higgs states which, if observed at the Large Hadron Collider, will help to constrain the underlying UV structure of the strong dynamics. Doubly charged Higgs bosons are well-motivated scalar degrees of freedom in this context. Their phenomenology in typical composite scenarios can differ from well-established Higgs triplet extensions of the SM. Related search strategies are not necessarily adapted to such a scenario as a consequence. In this paper we discuss the sensitivity reach to doubly charged Higgs bosons with decays into pairs of same-sign W bosons. While production cross sections are small, we show that significant constraints on H±±→W±W± can be obtained, providing a new opportunity to constrain the potential composite structure of the TeV scale up to mH±±≃800 GeV. [ABSTRACT FROM AUTHOR]

Perturbative probability conservation provides a strong constraint on the presence of new interactions of the Higgs boson. In this work we consider CP-violating Higgs interactions in conjunction with unitarity constraints in the gauge-Higgs and fermion-Higgs sectors. Injecting signal strength measurements of the recently discovered Higgs boson allows us to make concrete and correlated predictions of how CP violation in the Higgs sector can be directly constrained through collider searches for either characteristic new states or telltale enhancements in multi-Higgs processes. [ABSTRACT FROM AUTHOR]

Dark sectors with strong interactions have received considerable interest. Assuming the existence of a minimally coupled dark sector which runs to strong interactions in the infrared, we address the question whether the scaling behavior of this dark sector can be observed in missing energy signatures at present and future hadron colliders. We compare these findings to the concrete case of self-interacting dark matter and demonstrate that the energy dependence of high-momentum transfer final states can in principle be used to gain information about the UV structure of hidden sectors at future hadron colliders, subject to large improvements in systematic uncertainties, which could complement proof-of-principle lattice investigations. We also comment on the case of dark Abelian U(1) theories. [ABSTRACT FROM AUTHOR]

Disformally coupled, light scalar fields arise in many of the theories of dark energy and modified gravity that attempt to explain the accelerated expansion of the Universe. They have proved difficult to constrain with precision tests of gravity because they do not give rise to fifth forces around static nonrelativistic sources. However, because the scalar field couples derivatively to standard model matter, measurements at high-energy particle colliders offer an effective way to constrain and potentially detect a disformally coupled scalar field. Here we derive new constraints on the strength of the disformal coupling from LHC run 1 data and provide a forecast for the improvement of these constraints from run 2. We additionally comment on the running of disformal and standard model couplings in this scenario under the renormalization group flow. [ABSTRACT FROM AUTHOR]

CP violation beyond the Standard Model (SM) is a crucial missing piece for explaining the observed matter-antimatter asymmetry in the Universe. Recently, the ATLAS experiment at the Large Hadron Collider performed an analysis of electroweak Zjj production, thereby excluding the SM locally at 95% confidence level in the measurement of CP-sensitive observables. We take the excess interpretation in terms of anomalous gauge-Higgs interactions at face value and discuss further steps that are required to scrutinize its origin. In particular, we discuss the relevance of multiboson production using adapted angular observables to show how they can be used to directly tension the reported Zjj excess in a more comprehensive analysis. To connect the excess to a concrete UV scenario for which the underlying assumptions of the Zjj analysis are valid, we identify vectorlike leptons as a candidate theory consistent with the observed CP-odd Wilson coefficient hierarchy observed by ATLAS. We perform a complete one-loop matching calculation to motivate further model-specific and correlated new physics searches. In parallel, we provide estimates of the sensitivity reach of the LHC's high luminosity phase for this particular scenario of CP violation in light of electroweak precision and Run-2 Higgs data. These provide strong constraints on the model's CP-even low-energy phenomenology, but also inform the size of the CP-odd SM deformation indirectly via our model hypothesis. [ABSTRACT FROM AUTHOR]

In models with extended scalars and CP violation, resonance searches in double Higgs final states stand in competition with related searches in top quark final states as optimal channels for the discovery of beyond the Standard Model (BSM) physics. This complementarity is particularly relevant for benchmark scenarios that aim to highlight multi-Higgs production as a standard candle for the study of BSM phenomena. In this paper, we compare interference effects in tt final states with correlated phenomena in double Higgs production in the complex singlet and the complex two-Higgs-doublet models. Our results indicate that the BSM discovery potential in di-Higgs searches can be underestimated in comparison to tt resonance searches. Top pair final states are typically suppressed due to destructive signal-background interference, while h h final states can be enhanced due to signal-signal interference. For parameter choices where the two heavy Higgs resonances are well separated in mass, top final states are suppressed relative to the naive signal expectation, while estimates of the production cross section times branching ratio remain accurate at the O (10%) level for double Higgs final states. [ABSTRACT FROM AUTHOR]

Physics beyond the Standard Model can manifest itself as both new light states and heavy degrees of freedom. In this paper, we assume that the former comprise only a sterile neutrino, N. Therefore, the most agnostic description of the new physics is given by an effective field theory built upon the Standard Model fields as well as N. We show that Higgs phenomenology provides a sensitive and potentially crucial tool to constrain effective gauge interactions of sterile neutrinos, not yet probed by current experiments. In parallel, this motivates a range of new Higgs decay channels with clean signatures as candidates for the next LHC runs, including h→γ+pTmiss and h→γγ+pTmiss. [ABSTRACT FROM AUTHOR]

Current projections suggest that the LHC will have only limited sensitivity to di-Higgs production in the Standard Model (SM), possibly even after the completion of its high-luminosity phase. Multi-Higgs final states play a fundamental role in many extensions of the SM as they are intrinsically sensitive to modifications of the Higgs sector. Therefore, any new observation in multi-Higgs final states could be linked to a range of beyond the SM (BSM) phenomena that are not sufficiently addressed by the SM. Extensions of the Higgs sector typically lead to new phenomenological signatures in multi-Higgs final states that are vastly different from the SM expectation. In this work, we provide a range of signature-driven benchmark points for resonant and nonresonant BSM di-Higgs production that motivate non-SM kinematic correlations and multifermion discovery channels. Relying on theoretically well-motivated assumptions, special attention is devoted to the particular case where the presence of new physics will dominantly manifest itself in multi-Higgs final states. [ABSTRACT FROM AUTHOR]

Trilinear Z boson interactions are sensitive probes both of new sources of CP violation in physics beyond the standard model and of new particle thresholds. Measurements of trilinear Z interactions are typically interpreted in the frameworks of anomalous couplings and effective field theory, both of which require care in interpretation. To obtain a quantitative picture of the power of these measurements when interpreted in a TeV-scale context, we investigate the anatomy of ZZZ interactions and consider two minimal and perturbative simplified models which induce such interactions through new scalar and fermion loops at the weak scale, focusing on ZZ and vector boson fusion-induced Zjj production at the LHC and ZZ production at a future e+e- collider. We show that both threshold and non-threshold effects often are small compared to the sensitivity of the LHC, while the increased sensitivity of a future lepton collider should allow us to constrain such scenarios through associated electroweak precision effects complementary to direct searches at hadron colliders. [ABSTRACT FROM AUTHOR]

Scalar dark energy fields that couple to the standard model can give rise to observable signatures at the LHC. In this work, we show that tt+missing energy and monojet searches are suitable probes in the limit where the dark energy scalar is stable on collider distances. We discuss the prospects of distinguishing the dark energy character of new physics signals from dark matter signatures and the possibility of probing the self-interactions of the dark energy sector. [ABSTRACT FROM AUTHOR]

We consider scalar extensions of the Standard Model (SM) and their effective field theoretic generalizations to illustrate the phenomenological connection between precision measurements of the anomalous magnetic moment of the muon aμ, precision Higgs measurements, and direct collider sensitivity. To this end, we consider charged beyond Standard Model (BSM) scalar sectors of the Zee-Babu type for which we develop a consistent and complete dimension-5 and -6 effective field theory extensions. This enables us to track generic new physics effects that interact with the SM predominantly via radiative interactions. While the operator space is high dimensional, the intersection of exotics searches at the Large Hadron Collider (LHC), Higgs signal strength, and anomalous muon magnetic measurements is manageably small. We find that consistency of LHC Higgs observations and aμ requires a significant deformation of the new states' electroweak properties. Evidence in searches for doubly charged scalars as currently pursued by the LHC experiments can be used to further tension the BSMEFT parameter space and resolve blind directions in the effective field theory (EFT)-extended Zee-Babu scenario. [ABSTRACT FROM AUTHOR]

We consider the phenomenological implications of charged scalar extensions of the Standard Model (SM) Higgs sector in addition to effective field theory (EFT) couplings of this new state to SM matter. We perform a detailed investigation of modifications of loop-induced decays of the 125 GeV Higgs boson, which receives corrections from the propagating charged scalars alongside one-loop EFT operator insertions and demonstrate that the interplay of H→γγ and H→Zγ decays can be used to clarify the additional states phenomenology in case a discovery is made in the future. In parallel, EFT interactions of the charged Higgs can lead to a decreased sensitivity to the virtual presence of charged Higgs states, which can significantly weaken the constraints that are naively expected from the precisely measured H→γγ branching ratio. Again H→Zγ measurements provide complementary sensitivity that can be exploited in the future. [ABSTRACT FROM AUTHOR]